Eighty-year-old houses, mostly owner-occupied
Census figures describe a city with almost no apartments: 4,377 of San Marino's 4,439 homes are detached single-family houses, and 3,237 of the 3,910 occupied homes are owner-occupied. The median year built is 1943, so a typical house here has stood for more than eighty years.
Age matters more than price when it comes to pests. Original wood framing, raised floors over crawl spaces, chimneys, old attic vents and decades of additions and remodels leave seams where rodents, ants and spiders are likely to find a way in. Because so many owners plan to stay for years, sealing those openings tends to pay off better than repeated spot treatments.
Sources: [1]
What San Marino's City Hall teaches about termites
Over Thanksgiving 2020 the city tented its entire City Hall. The San Marino Tribune reported that termites had come back after an earlier fumigation in 2012, that spiders and a tiny gnat living in the plumbing were also part of the problem, and that milder measures had not solved it. Fumigation and repairs came to $84,200.
If a public building that had already been fumigated once can be re-infested within eight years, a privately owned wood-frame house from the 1940s deserves a careful look too. PesPro does not tent homes or sell termite fumigation. During a general pest inspection we point out what we see — small pellet piles under windowsills, blistered or hollow-sounding trim, discarded wings near windows — and recommend that you have a licensed termite specialist evaluate it.
Sources: [13][1]
West Nile virus arrives late in the season here
The Greater Los Angeles County Vector Control District has recorded West Nile–positive mosquitoes in San Marino in 2021, 2022, 2023, 2024 and again in 2026; 2025 was the only recent year without one. The worst season was 2022: in early July two of the district's first three positive samples of the year came from San Marino (ZIP 91108), a story picked up by FOX 11 and the San Marino Tribune, and by year's end the city had 10 positive mosquito samples and 2 positive dead birds.
The timing is worth noticing. The single 2023 detection came on November 8, and in 2026 the first positive sample did not appear until September 22, with four by the district's October 19 update. For San Marino households, autumn is clearly not the end of mosquito season. Mosquito surveillance and treatment belong to the district — San Marino is not part of the San Gabriel Valley Mosquito & Vector Control District's service list — and PesPro does not offer mosquito control.
Sources: [7][6][5][4][3][2][8][9][11][16]
Fountains, ponds and the invasive Aedes mosquito
At a city town hall at Crowell Public Library in May 2019, the vector control district explained that the invasive Aedes mosquito — a small black-and-white biter that can carry Zika, dengue, yellow fever and chikungunya — had reached San Marino and nearby communities in recent years. In summer it can go from egg to adult in five to seven days, which is why the district asks residents to check containers weekly.
Large gardens multiply those containers. The district's checklist, repeated in local coverage, includes clogged rain gutters, rain barrels, neglected green pools, bird baths and ornamental ponds, where mosquito fish can help. When our technicians are on your property for ants, rodents or wasps, we mention any standing water we notice so you can deal with it or report it to the district.
Sources: [12][11][10]
Mature trees, Lacy Park and the pests they shelter
Greenery is part of the city's history: Lacy Park, bought by the city in 1925, was laid out as a botanical garden on the site of the former Wilson Lake, with trees donated from the Huntington estate. Many private lots carry the same kind of tall, old canopy.
That canopy is a likely highway for roof rats, which climb trunks and travel along branches that rest on a roof. Dense shrubs and irrigated beds also suit Argentine ants, and hollow trees or gaps in old siding can attract bees and yellowjackets. Our inspections in San Marino start with the trees and rooflines before we look inside.
Sources: [14]
Our website in Simplified Chinese: pespro.com/zh
Chinese is the most common language spoken at home in San Marino: 43.8% of residents age five and older speak it, slightly more than the 43.3% who speak only English, and about 45% of those Chinese speakers report speaking English less than very well. That is why the PesPro website has a Simplified Chinese version at pespro.com/zh, with our service pages and a contact form, so anyone in the household can read what a treatment involves and request a visit through the Chinese form.
To be clear about the visit itself: our technicians speak English and Spanish. Many families find it helpful to read the Chinese pages together before the appointment and keep them open during it.
Sources: [1]
